IP TELEPHONY: From Evolution to Revolution… from Emerging to the Inevitable

The world of telephony has changed a lot since Alexander Graham Bell’s

first call more than a century ago. The major breakthroughs have been the

introduction of automatic exchanges, digitization of those exchanges,

implementation of digital telephony, use of satellites and fiber optics for

communications and the coming of mobile telephony. These have all been

improvements over the basic theme of an end-to-end circuit switched

connectivity.

However, the coming of the Internet and the subsequent development of

Internet Protocol Telephony, IP Telephony in short, changed all that. IP

telephony encompasses many different ways of transmitting voice, fax and related

services over packet-switched IP-based networks. It is also used as a generic

term to cover voice over Frame Relay and voice over xDSL. For the record, IP

telephony can be divided into two major sub-groups — Internet Telephony and

Voice over IP. While the former uses the public Internet network for voice

traffic and is highly disorganized, with little QoS guarantee; the latter refers

to voice traffic over a managed IP-based network. There are QoS issues involved

in VoIP also, but they are being worked out, allowing a number of carriers

worldwide to offer integrated voice and data services.

The Evolution of IP Telephony

While Internet telephony has usually meant low cost or even free voice calls,

VoIP has been much more than this for the core network operators, local

exchanges and corporate enterprise.

Ravi Shekhar Pandey